const Crypto = require('./crypto.js');

(function () {

  // Shortcut
  var util = Crypto.util;

  // Public API
  var SHA1 = Crypto.SHA1 = function (message, options) {
    var digestbytes = util.wordsToBytes(SHA1._sha1(message));
    return options && options.asBytes ? digestbytes :
      options && options.asString ? util.bytesToString(digestbytes) :
        util.bytesToHex(digestbytes);
  };

  // The core
  SHA1._sha1 = function (message) {

    var m = util.stringToWords(message),
      l = message.length * 8,
      w = [],
      H0 = 1732584193,
      H1 = -271733879,
      H2 = -1732584194,
      H3 = 271733878,
      H4 = -1009589776;

    // Padding
    m[l >> 5] |= 0x80 << (24 - l % 32);
    m[((l + 64 >>> 9) << 4) + 15] = l;

    for (var i = 0; i < m.length; i += 16) {

      var a = H0,
        b = H1,
        c = H2,
        d = H3,
        e = H4;

      for (var j = 0; j < 80; j++) {

        if (j < 16) w[j] = m[i + j];
        else {
          var n = w[j - 3] ^ w[j - 8] ^ w[j - 14] ^ w[j - 16];
          w[j] = (n << 1) | (n >>> 31);
        }

        var t = ((H0 << 5) | (H0 >>> 27)) + H4 + (w[j] >>> 0) + (
          j < 20 ? (H1 & H2 | ~H1 & H3) + 1518500249 :
            j < 40 ? (H1 ^ H2 ^ H3) + 1859775393 :
              j < 60 ? (H1 & H2 | H1 & H3 | H2 & H3) - 1894007588 :
                (H1 ^ H2 ^ H3) - 899497514);

        H4 = H3;
        H3 = H2;
        H2 = (H1 << 30) | (H1 >>> 2);
        H1 = H0;
        H0 = t;

      }

      H0 += a;
      H1 += b;
      H2 += c;
      H3 += d;
      H4 += e;

    }

    return [H0, H1, H2, H3, H4];

  };

  // Package private blocksize
  SHA1._blocksize = 16;

})();

module.exports = Crypto;